Genetic factors into aggressive behaviour: XYY chromosomes

Psychology unit 3 aggression Genetic factors into aggressive behaviour- XYY chromosomeDescriptionSome people have an extra Y chromosome. As males are more aggressive thanfemales this extra Y chromosome is thought to cause additional aggressivebehaviours.Evidence/evaluationJacobs found that 3% of inmates had the XYY chromosome compared to 0.1% ofthe wider population. This suggests that XYY might be linked to criminality. Thiscould also be due to lack of intelligence meaning these criminals are the ones whoare most likely to be caught. Additionally it has been found that XYY's tend tohave higher testosterone levels and lack intelligence.Witken found that whilst XYY's were more likely to commit crimes, their crimesdidn't appear to be aggressive in nature. This means that XYY is more likely to belinked to criminality and not to aggression.